Hi,
A few comments on various points :
- if you try to produce 3D printer parts found on the internet, they are not designed with CNC milling in mind -> you're probably in for a big disappointment if you try to make them with a CNC mill. You'll probably have to redesign some of it.
- a heated bed is not always necessary depending on the material you intend to use. PLA can be printed without and is a very good beginner material as it has low shrink rate (-> little to no warp). While not a specialist, I would say that you can do that later as a retrofit.
- If you say you have little electronics experience and 2 weeks to complete, I would not design my own board...
- In fact, given your short time frame, I think you would be better off ordering a kit to assemble. Or is it a budget issue ?